Cats will be raised with monocular or binocular deprivation and studied as adults. We will use quantitative, electrophysiological techniques to study the effects of deprivation on receptive fields of striate cortical neurons, particularly concentrating on neurons with receptive field locations well away from the area centralis. We will compare their data to those previously accumulated from normal cats. These data will extend previous work and also will further elucidate our theory involving a developmental mechanism of binocular competition. The status of neurons in the cortical monocular segment of deprived cats will help determine if, as predicted, this mechanism applies to monocularly, but not binocularly, deprived cats. Other less extensive experiments will be directed at the question of the permanence of deprivation effects in the lateral geniculate nucleus (Y-cell loss) and superior colliculus (loss of Y-indirect input), and at determining some of the environmental conditions necessary for the initiation of binocular competition. Behavioral visual perimetry testing will be continued in order to test for correlates for the above data, and finally, we hope to improve the quantitative capacities of this perimetry technique.